© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—-6-1 Network Environment Management Discovering Neighbors on the Network

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-2 Cisco Discovery Protocol  Cisco Discovery Protocol is a proprietary utility that provides a summary of directly connected switches, routers, and other Cisco devices.  Cisco Discovery Protocol discovers neighboring devices, regardless of which protocol suite they are running.  Physical media must support the SNAP encapsulation.

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-3 Discovering Neighbors with Cisco Discovery Protocol  Cisco Discovery Protocol runs on Cisco IOS devices.  Summary information includes: –Device identifiers –Address list –Port identifier –Capabilities list –Platform

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-4 Using Cisco Discovery Protocol RouterA#show cdp ? entry Information for specific neighbor entry interface CDP interface status and configuration neighbors CDP neighbors entries traffic CDP statistics RouterA(config)#no cdp run RouterA(config)#interface serial0/0/0 RouterA(config-if)#no cdp enable

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-5 Using Cisco Discovery Protocol RouterA#show cdp ? entry Information for specific neighbor entry interface CDP interface status and configuration neighbors CDP neighbor entries traffic CDP statistics … RouterA(config)#no cdp run ! Disable CDP Globally RouterA(config)#interface serial0/0/0 RouterA(config-if)#no cdp enable ! Disable CDP on just this interface

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-6 Using the show cdp neighbors Command RouterA#show cdp neighbors Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge S - Switch, H - Host, I - IGMP, r - Repeater Device ID Local Intrfce Holdtme Capability Platform Port ID SwitchA fa0/0 122 S I WS-C2960- fa0/2 RouterB s0/0/0 177 R S I 2811 s0/0/1

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-7 Using the show cdp entry Command Device ID: RouterB Entry address(es): IP address: Platform: Cisco 2811, Capabilities: Router Switch IGMP Interface: Serial0/0/0, Port ID (outgoing port): Serial0/0/1 Holdtime : 155 sec Version : Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(12), RELEASE SOFTWARE (fc1) Technical Support: Copyright (c) by Cisco Systems, Inc. Compiled Fri 17-Nov-06 12:02 by prod_rel_team

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-8 Additional Cisco Discovery Protocol Commands RouterA#show cdp traffic CDP counters : Total packets output: 8680, Input: 8678 Hdr syntax: 0, Chksum error: 0, Encaps failed: 5 No memory: 0, Invalid packet: 0, Fragmented: 0 CDP version 1 advertisements output: 0, Input: 0 CDP version 2 advertisements output: 8680, Input: 8678 RouterA#show cdp interface s0/0/0 Serial0/0/0 is up, line protocol is up Encapsulation PPP Sending CDP packets every 60 seconds Holdtime is 180 seconds

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-9 Creating a Network Map

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-10 Summary  Cisco Discovery Protocol is an information-gathering tool used by network administrators to obtain information about directly connected devices.  Cisco Discovery Protocol exchanges hardware and software device information with its directly connected Cisco Discovery Protocol neighbors.  Cisco Discovery Protocol on a router can be enabled or disabled as a whole or on a port-by-port basis.  The show cdp neighbors command displays information about the Cisco Discovery Protocol neighbors of a router.  The show cdp entry, show cdp traffic, and show cdp interface commands display detailed Cisco Discovery Protocol information on a Cisco device.  Using the information obtained from the show cdp command output, a network topology map can be created to aid troubleshooting.

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—6-11